/**
* touch.js
* @fileOverview 移动端touch事件
* @author Tim
* @version 1.0
* @date 2013-09-02
* @extends jquery.1.8.3
* @remark 针对于移动端web的click事件优化
*/

define(['jquery'], function ($) {

; (function ($) {
    var touch = {},
      touchTimeout, tapTimeout, swipeTimeout,
      longTapDelay = 750, longTapTimeout

    function parentIfText(node) {
        return 'tagName' in node ? node : node.parentNode
    }

    function swipeDirection(x1, x2, y1, y2) {
        var xDelta = Math.abs(x1 - x2), yDelta = Math.abs(y1 - y2)
        return xDelta >= yDelta ? (x1 - x2 > 0 ? 'Left' : 'Right') : (y1 - y2 > 0 ? 'Up' : 'Down')
    }

    function longTap() {
        longTapTimeout = null
        if (touch.last) {
            touch.el.trigger('longTap')
            touch = {}
        }
    }

    function cancelLongTap() {
        if (longTapTimeout) clearTimeout(longTapTimeout)
        longTapTimeout = null
    }

    function cancelAll() {
        if (touchTimeout) clearTimeout(touchTimeout)
        if (tapTimeout) clearTimeout(tapTimeout)
        if (swipeTimeout) clearTimeout(swipeTimeout)
        if (longTapTimeout) clearTimeout(longTapTimeout)
        touchTimeout = tapTimeout = swipeTimeout = longTapTimeout = null
        touch = {}
    }

    $(document).ready(function () {
        var now, delta

        $(document.body)
          .bind('touchstart', function (e) {
              now = Date.now()
              delta = now - (touch.last || now)
              touch.el = $(parentIfText(e.originalEvent.touches[0].target))
              touchTimeout && clearTimeout(touchTimeout)
              touch.x1 = e.originalEvent.touches[0].pageX
              touch.y1 = e.originalEvent.touches[0].pageY
              if (delta > 0 && delta <= 250) touch.isDoubleTap = true
              touch.last = now
              longTapTimeout = setTimeout(longTap, longTapDelay)
          })
          .bind('touchmove', function (e) {
              cancelLongTap()
              touch.x2 = e.originalEvent.touches[0].pageX
              touch.y2 = e.originalEvent.touches[0].pageY
              if (Math.abs(touch.x1 - touch.x2) > 10)
                  e.preventDefault()
          })
          .bind('touchend', function (e) {
              cancelLongTap()

              // swipe
              if ((touch.x2 && Math.abs(touch.x1 - touch.x2) > 30) ||
                  (touch.y2 && Math.abs(touch.y1 - touch.y2) > 30))

                  swipeTimeout = setTimeout(function () {
                      touch.el.trigger('swipe')
                      touch.el.trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)))
                      touch = {}
                  }, 0)

                  // normal tap
              else if ('last' in touch)

                  // delay by one tick so we can cancel the 'tap' event if 'scroll' fires
                  // ('tap' fires before 'scroll')
                  tapTimeout = setTimeout(function () {

                      // trigger universal 'tap' with the option to cancelTouch()
                      // (cancelTouch cancels processing of single vs double taps for faster 'tap' response)
                      var event = $.Event('tap')
                      event.cancelTouch = cancelAll
                      touch.el.trigger(event)

                      // trigger double tap immediately
                      if (touch.isDoubleTap) {
                          touch.el.trigger('doubleTap')
                          touch = {}
                      }

                          // trigger single tap after 250ms of inactivity
                      else {
                          touchTimeout = setTimeout(function () {
                              touchTimeout = null
                              touch.el.trigger('singleTap')
                              touch = {}
                          }, 250)
                      }

                  }, 0)

          })
          .bind('touchcancel', cancelAll)

        $(window).bind('scroll', cancelAll)
    });
    var eventList = ['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown', 'doubleTap', 'tap', 'singleTap', 'longTap'];
    if (eventList.forEach) {
        eventList.forEach(function (m) {
            $.fn[m] = function (callback) { return this.bind(m, callback) }
        })
    }
})(jQuery)

})